Since light is the medium of the photographer, working with an absence of light can be difficult. It requires skill and an understanding of the way light affects the image. Nighttime photography can offer artistic opportunities that daytime cannot, as the photographer can minutely control the amount of light being used. By using lenses with extremely wide apertures, on and off camera flash and slow shutter speeds, the photographer can create a range of effects for an image.
Fast Glass
Fast glass is a term for lenses that have wide aperture settings. The "speed" of the glass refers to the aperture, the wider the aperture setting can go, the faster the lens is considered to be.
Average lenses have apertures that open to around 3.5. Faster lenses can go to 1.8, 1.4 or lower. These lenses allow two and four times the light in. However, as with most photography concepts, there is a reciprocal rule--the wider the aperture, the narrower the plane of focus will be. Less of the image will be focused; at f 1.8, this distance is measured in inches. The photographer must then take great care in focusing images and choosing subjects.
Shutter Speed
Shutter speed is another way to alter the amount of light that enters the camera. A fast shutter speed will effectively "freeze" action, capturing a subject with little motion blur; a slow shutter speed allows more light to enter the camera by holding the shutter open longer. In the case of night photography, slow shutter speeds can be used to great effect, as any movement or light will be recorded on the film. This can be used to show motion in an image.
Shutter speed works hand in hand with aperture---as you increase one, it becomes necessary to decrease the other. In order to freeze motion, a faster shutter speed must be selected, so decreasing the f-stop (making the aperture wider) will allow more light in. Conversely, to use a slow shutter speed, the f-stop must be increased.
Flash
Using flash in night time photography can help immensely, especially if the aim is to take a clear photo of a moving object. The flash burst works to illuminate the subject for a brief moment, which is captured on the film---coupled with the correct shutter speed and aperture, only this moment will be recorded and other motion will not be detectable to the camera.
There are two types of flash used in this manner. Front curtain sync means the flash burst is synchronized to go off at the exact moment when the shutter is open fullest. Motion blur will appear in front of the subject. Rear curtain sync freezes motion at the end of the exposure, synchronizing the flash burst to the last part of the shutter's movement. This gives a more standard look and any captured motion blur will be behind the subject.
Flash can be a harsh method of lighting. Using an on-camera flash unit or flash head pointed directly at the subject will cause high contrast and harsh shadows. To soften this effect, the photographer may use off camera flash fired remotely or aim the flash head away from the subject and allow a diffuser, bounce card or other object to bounce light back onto the subject. This makes for a softer, more evenly lit image; however, this will interfere with flash metering, so the photographer must remember to compensate for the amount of light lost by either decreasing the shutter speed, selecting a wider aperture or increasing the power of the flash burst.
Tags: flash burst, shutter speed, slow shutter, amount light, wider aperture, aperture wider, blur will
